The latest evidence comes from a new study of probiotic bacteria, the microorganisms typically found in yogurt and dairy products. While most investigations of probiotics have focused on their gastrointestinal benefits—the bacteria reduce the symptoms of diarrhea and irritable bowel syndrome—this new research explored the effect of probiotics on the brain.
The experiment, led by Javier Bravo at University College Cork in Ireland, was straightforward. First, he fed normal lab mice a diet full of probiotics. Then, Mr. Bravo’s team tested for behavioral changes, which were significant: When probiotic-fed animals were put in stressful conditions, such as being dropped into a pool of water, they were less anxious and released less stress hormone.
How did the food induce these changes? The answer involves GABA, a neurotransmitter that reduces the activity of neurons. When Mr. Bravo looked at the brains of the mice, he found that those fed probiotics had more GABA receptors in areas associated with memory and the regulation of emotions.
“Life is infinitely stranger than anything which the mind of man could invent. We would not dare to conceive the things which are really mere commonplaces of existence. If we could fly out of that window hand in hand, hover over this great city, gently remove the roofs, and peep in at the queer things which are going on, the strange coincidences, the plannings, the cross-purposes, the wonderful chains of events, working through generations, and leading to the most outre results, it would make all fiction with its conventionalities and foreseen conclusions most stale and unprofitable.”—Sir Arthur Conan Doyle (via black-wolves)